Alcohol Use at Any Level Linked to Higher Dementia Risk, Large Study Finds

Alcohol use of any amount may increase the risk of developing dementia, according to findings from a large-scale study combining observational and genetic analyses, published in BMJ Evidence-Based Medicine in September 2025.

The investigation pooled data from 2 population-based cohorts—the US Million Veteran Programme (MVP) and the UK Biobank—encompassing 559 559 adults aged 56 to 72 years at baseline, with mean follow-up of 4 years in the US cohort and 12 years in the UK cohort. Over the study period, 14 540 participants developed dementia and 48 034 died. Genetic analyses further drew on data from more than 2.4 million individuals across 45 genome-wide association study (GWAS) cohorts.

In conventional observational analyses, researchers observed a U-shaped association: nondrinkers, heavy drinkers (>40 drinks per week), and individuals with alcohol use disorder (AUD) were at higher risk compared with light drinkers (<7 drinks per week). For example, heavy drinkers demonstrated a 41% higher dementia risk (hazard ratio [HR], 1.41; 95% CI, 1.15-1.74), and those with AUD had a 51% increased risk (HR, 1.51; 95% CI, 1.42-1.60).

However, Mendelian randomisation (MR) analyses using genetic proxies contradicted the apparent protective effect of light drinking. The genetic data showed a monotonic increase in dementia risk with greater alcohol intake. A 1-SD increase in log-transformed drinks per week was associated with a 15% rise in dementia risk (odds ratio [OR], 1.15; 95% CI, 1.03-1.27), while a twofold increase in AUD prevalence corresponded to a 16% higher risk (OR, 1.16; 95% CI, 1.03-1.30).

Longitudinal analyses suggested reverse causation may underlie prior reports of benefits with light drinking. Participants who went on to develop dementia showed a faster decline in alcohol consumption before diagnosis compared with controls, indicating that early cognitive decline may have led to reduced drinking, thereby biasing observational results.

The study also examined outcomes across diverse ancestry groups, with elevated dementia risk linked to AUD observed in both African and Latin American ancestry populations.

The authors concluded that “these findings provide evidence for a relationship between all types of alcohol use and increased dementia risk.” They added that halving the population prevalence of AUD could reduce dementia cases by as much as 16%, underscoring alcohol reduction as a potential prevention strategy.

Reference: Topiwala A, Levey DF, Zhou H, et al. Alcohol use and risk of dementia in diverse populations: evidence from cohort, case–control and Mendelian randomisation approaches. BMJ Evid Based Med. Published online September 23, 2025. doi:10.1136/bmjebm-2025-113913